PRINCIPLE DIAGRAM
LEGEND
BM
Modulating coil
CA
Ignition control unit Honeywell
Circulating pump
CiR
Control electrode
EC
ES
Spark electrode
L
Line
MAX R Max. heating setting
Neutral
N
PF
Fumes pressure switch
Pma Lack of water pressure switch
PR
Reset push-button
P.risc. Heating potentiometer
PS
Hot water pressure switch
P.san. Hot water potentiometer
RT
RL3 relay contact
NOTE: Slow ignition (RLA) is of the mechanical type positioned on the gas valve as illustrated in the figure on page 65.
RS
R4 relay contact
RP
RL2 relay contact
Anti-interference resistance
RF
Lock-out warning light
SB
SR
Heating detector
SS
Hot water/water-heater detector
SW1 Function selector
TIMER Boiler timer adjustment
TR1
Transformer
TST
Total safety thermostat
V
3-way valve
Gas valve
VG
VN
Fan
45